95
votes
What is the slowest fixed-wing airplane?
The Gossamer Albatross is a human-powered plane with a top speed of 29 km/h (18mph).
It was used to cross the English Channel and seems to meet the criteria of the question.
83
votes
Why is indicated airspeed rather than ground speed used during the takeoff roll?
Because wings work on air moving past them, not ground moving below them.
Heck, in a 35 knot headwind, the Antonov-2 could be rolling backwards at 2 knots and still take off!
65
votes
Accepted
Would a slower speed and lower altitude reduce fatal incidents?
I'd like to answer this question by debunking the premise of the question: that most plane crashes happen when planes fall out of the sky, and that it's like rock climbing where the higher you are, ...
- 6,803
61
votes
What is the slowest fixed-wing airplane?
The Antonov AN-2 has no stall speed quoted in the operating manual and can fly under full control at about 30 mph. Thus if the headwind is sufficiently large the aircraft will move backwards with ...
- 5,522
61
votes
Would a slower speed and lower altitude reduce fatal incidents?
It would likely create a more deadly situation.
In aviation altitude is your friend. Generally speaking altitude in the case of an emergency buys you time to work the problem. Generally you want to ...
- 102k
47
votes
What is the slowest fixed-wing airplane?
The Harrier, Yak-38, Yak-141, XV-15, and V-22 are all fixed wing aircraft. All can hover in mid air, controlled.
So they are in controlled flight at 0 velocity.
At least the Harrier can even be in ...
- 16.1k
43
votes
Accepted
What is a jet (unit) shown in Windows 10 calculator?
It is not a unit. It is just Microsoft trying to be funny. Or to convey an idea of the magnitude.
Thanks @Jackie for pointing out that around March 2019, Microsoft has released this calculator as ...
- 10.8k
43
votes
Why is indicated airspeed rather than ground speed used during the takeoff roll?
Because what determines the amount of lift generated is the indicated airspeed, not the ground speed. As usual, it is always easier to think about an extreme case. If you have an aircraft with VR (...
- 4,505
43
votes
Accepted
What is the commercial passenger aircraft top speed record?
"Speed" is not a singular term in aviation. There are many different ways to measure speed. See for example Why is there a difference between GPS Speed and Indicator speed? Most commercial jets cruise ...
- 36.9k
39
votes
Accepted
The SR-71 flew at 2193 mph. Mathematically, how can this be Mach 3.3?
The SR-71 was only capable of Mach 3.3 flight at altitude. You can see the limitations in the pilot's operating handbook(POH) for the aircraft:
At higher altitudes the relative speed of sound is ...
- 102k
33
votes
Accepted
Do Air Traffic Controllers have to remember stall speeds for different aircraft?
No because aircraft are categorized by their speed at the runway threshold (1.3 times stall speed).
VAT —Speed at threshold used by ICAO (1.3 times stall speed in the landing configuration at maximum ...
- 76.5k
31
votes
How does it feel like to be outside a flying airplane?
It won't be pleasant. The main result of being exposed outside at altitude, besides the obvious hypothermia, frostbite and hypoxia, will be bruising from the 280-ish knot slipstream (it's the ...
- 134k
30
votes
Accepted
Does a sudden drop of the velocity of the headwind affect the airspeed by lowering it?
Your airspeed does not remain constant because of inertia: it takes more time for the airplane to adapt to the new relative wind, compared to the time it takes for the wind to change.
Example One: ...
- 39.8k
30
votes
Why would 2 aircraft fitted with the P&W PT6 Engine have different top speed?
The P&W PT6 comes in many different varieties. The smallest PT have 500hp while the largest have 1700hp. It is not the "same engine" as you state in your question.
The standard Caravan has ...
- 37.9k
29
votes
What is the commercial passenger aircraft top speed record?
Other than the TU-144 and Concorde, the record for the fastest True Airspeed in an airliner probably belongs to a DC-8.
Wikipedia Douglas DC-8
On August 21, 1961, a Douglas DC-8 broke the sound ...
- 37.9k
28
votes
Accepted
Why is a 737 Original speed-restricted below 10 kft with inoperative windscreen heating?
To reduce damage in case of a bird strike.
The restriction is not only for the 737-100 and -200 models, the 737 NG QRH says:
WINDOW HEAT OFF
In flight:
WINDOWS HEAT switch (affected window) ..... OFF
...
- 57.6k
25
votes
Accepted
Why must Vr be set so precisely?
This answer is written for air transport category aircraft.
Introduction
During take-off there are three operationally significant speeds that ensure a safe take-off:
V1 - the take-off decision speed
...
- 83.8k
23
votes
Accepted
What is the reason for changing the speed reference (IAS or Mach number) with altitude?
Aircraft are limited by both air speed (VMO, affects loads on the structures) and Mach (MMO, formation of shock waves resulting in buffet).
At low altitudes, the speed of sound is high so an aircraft ...
- 73.5k
22
votes
Is it right to extend flaps only in the white arc?
Yes you must slow down to the white arc, or whatever your flap extension speed is for a given condition, regardless. If you are 10kts above the white arc and drop flaps anyway, it's not going to make ...
- 134k
22
votes
Why would 2 aircraft fitted with the P&W PT6 Engine have different top speed?
Even if the installed engine version was identical (which, as @MikeSowsun noted, is not always the case), different types have different weights, drag profiles, and may have different propellers ...
- 17.2k
21
votes
What is the slowest fixed-wing airplane?
now, if you're looking at modern, more commonly used transportation, powered paragliding would probably take the cake.
CC BY 3.0, https://en.wikipedia.org/w/index.php?curid=13110495
Powered ...
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21
votes
What is the commercial passenger aircraft top speed record?
I think I know what you're asking, and the Concorde-excluded answer is almost certianly the Convair 990 which could get just shy of Mach 1. From wikipedia:
The Convair 990A is still the fastest ...
- 134k
21
votes
How does it feel like to be outside a flying airplane?
This is from Irish Luck - Surviving Partial Ejection from A-6 Aircraft. In this incident, the bombardier/navigator's ejection seat came part way out of an A-6, leaving the head and upper body exposed. ...
- 3,719
19
votes
Would mechanical indicators have helped in the Air France 447 incident?
Unfortunately, if there had been a jazz band in the cockpit singing "The plane is stalling" it wouldn't have helped. If Moses had been in there carrying a stone tablet newly-carved by God himself ...
- 12.9k
19
votes
Accepted
Why do we need to know both groundspeed and airspeed?
Airspeed is critical for pilots, because it is what the airplane "feels" when it's flying. Too little airspeed and the wings won't generate enough lift to fly, too much and the plane can be damaged. (...
- 306
18
votes
What is the slowest fixed-wing airplane?
If you are including historical aircraft, the Wright Flyer averaged 10 fps (approx 6.8 mph or 11 kph) over it's first 120 foot flight in 1903.
Reference: https://airandspace.si.edu/exhibitions/wright-...
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17
votes
What will the pilot do if all the airspeed indicators fail?
Some aircraft have angle of attack indicator, but most don't even though they have the sensor and use it for stall warning.
What you normally have is an unreliable airspeed procedure. This generally ...
- 56.4k
17
votes
Accepted
Is it possible to accurately measure airspeed without pitot tube?
Technically speaking, inertial measurements are not sufficient to derive airspeed. You need pressure measurement (or airspeed measurement, see LIDAR). Pitot-static probes are the most usual and ...
- 1,557
Only top scored, non community-wiki answers of a minimum length are eligible